Greetings! I want to move this towel bar but cannot figure out how to detach its hardware from the wall. Brand is unknown. Help!

The bar itself is one piece, and its posts slide on over the two wall-mounted posts. Allen screws inserted from the bottom then secure the bar to the posts.

But once the bar is off, there’s no other obvious hardware. The chrome caps remain on the wall and have no screws in them anywhere. I’ve tried rotating them as if they’re threaded on but they don’t budge. Gently pulling on them does nothing either. Wall posts are the same story - no visible hardware, and they don’t seem to respond to any...external stimuli.

So, how in the heck do I get these suckers off?? Anyone?